Suggest Treatment For Irregular Periods

I have two children both born via emergency c- section in 2003 and 2007 due to foetal distress. Have been trying for a baby for 2 years without any luck. Have been suffering from a short period of 3 days and then a gap for 5 days followed by spotting or brown discharge of old blood for 5 days upto ovulation. This has been going on since my c-section in 2007. In the last 2 years have suffered from 4 pelvic infections and I have to take antibiotics to clear it. Have been referred to a gynaecologist. Hysteroscopy, hormonal blood tests, vaginal ultrasound show nothing. Everyhing is as it should be. Husbands sperm count is good. I get ovulation every month followed by s 16 day luteal phase. What is causing the irregular periods and difficulty conceiving?